Blessed Silence

After spending a couple days in Proving Grounds collecting the relevant achievements
the NPCs constant chatter gets tiresome and annoying pretty fast.

In the end I realized I couldn't stomach it any longer if I was going to visit again on alts.

Hence Blessed Silence was born.

It will filter out their yells both from the chatframe as well as the boss-emote frame.

It will instead print a single line on the chat frame with the current wave you're on so you can easier monitor your progress, as well as see how far you got on failed attempts.

With an extra step it will also silence the voice sounds.

BlessedSilence should work in every client locale.

Installation Instructions

Install the addon like any other by extracting BlessedSilence in your AddOns folder.

If you want to mute the voice sounds as well go into the BlessedSilence folder and find the Data subfolder.

Copy the Data subfolder then navigate back out to the root \World of Warcraft\ folder.

Paste the Data folder you got from BlessedSilence answering "yes" to any overwrite prompts. (*)

(*) This doesn't actually overwrite any of your installation files, they are safely packed inside .mpq data files, there is no risk to your WoW installation.
What it does is place 'muted' sound-files at the same path those packed files would occupy if they were expanded and since WoW looks for unpacked files before digging into the defaults it essentially silences them.

Uninstallation
If you followed steps 2,3,4 in the installation guide to silence the voices along-side the chat messages,
you will need to remove the extra sound folder from inside \World of Warcraft\Data\ to let the game once again look for the sounds in its packed .mpq files.

If you didn't use the procedure to override the voice files then just removing or disabling BlessedSilence from your AddOns folder is enough.